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Epidemic and emerging disease alerts in the Pacific as of 16 December 2025

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Highlights/updates since the last map was sent on PacNet on 9 December 2025:

Dengue

  • Cook Islands: On 22 May 2025, the Cook Islands Ministry of Health declared a dengue outbreak in Rarotonga. As of 14 December 2025, 290 cases were reported, with 272 recovered and 18 still active. Most of the cases are in the 10-19 age group, and no fatalities or severe dengue cases have been reported. Of the 50 samples serotyped, 47 were DENV-1 and 3 were DENV-2, confirming co-circulation. Authorities are conducting clean-up and mass spraying campaigns, urging the public to eliminate mosquito breeding sites, use repellents, wear protective clothing, and seek medical care if symptoms appear. The blue alert for DENV-1 and DENV-2 remains in effect. – Source: Cook Islands 2025 Dengue Outbreak Situation Report #71 (15 December 2025) shared with PPHSN Coordinating Body focal point on 16 December 2025.

  • Kiribati: The Ministry of Health and Medical Services (MHMS) confirmed a dengue outbreak on 24 April 2025, after a significant rise in confirmed cases. As of 11 December 2025, MHMS reported a total of 503 confirmed dengue cases and 1,510 suspected dengue cases with 68 hospitalisations, all of which have been discharged, and one confirmed death. There have been 5 new cases since the last report on 19 November 2025. Dengue cases range in age from 1 month to 95 years, with the most affected group being those aged 3 to 9 years. Among all reported cases, 55% are female and 45% male. The serotypes that are responsible for this current outbreak are Dengue Virus Type 1 (DENV-1) and Dengue Virus Type 2 (DENV-2), tested at VIDRL in Melbourne. The MHMS continues to promote health awareness on social media through posters, press releases, and videos. It continues to investigate cases, conduct house-to-house inspections in high-risk areas, eliminate mosquito breeding sites, and advise community members to maintain a clean and healthy environment. Based on the sustained decline in case numbers for the past four weeks, the blue alert for DENV-1 and DENV-2 remains in effect. – Source: Dengue Fever Situational Report #30 (11 December 2025) shared with PPHSN Coordinating Body focal point on 11 December 2025.

  • Samoa: As of 7 December 2025, Samoa Ministry of Health has recorded a cumulative total of 16,161 clinically diagnosed dengue cases since January 2025, including 4,650 laboratory-confirmed cases, and seven dengue-related deaths. Children under 15 years account for 74% of the cases, and the circulating serotypes remain predominantly DENV-1 (91%) and DENV-2 (9%). Case numbers decreased by 9% compared to the previous EpiWeek, with 78 new clinical cases of which 27 are lab-confirmed. There are no hospital admissions for this EpiWeek 49 (1–7 December 2025). The Ministry of Health continues its whole-of-government response through the Integrated Vector Control Committee, prioritizing source reduction, environmental sanitation, and widespread risk communication. The blue alert for DENV-1 and DENV-2 remains in effect. – Source: Dengue Fever Outbreak Situation Report in Samoa Issue No. 34, Epi-week 49: 1st – 7th December 2025 shared with PPHSN Coordinating Body focal point on 12 December 2025.

  • Tuvalu: The Tuvalu Department of Health declared a dengue outbreak on 5 June 2025. As of 12 December 2025, 938 suspected cases were tested, with 1 new case reported since the last update on 9 December 2025. The total number of confirmed positive cases is 249. The dengue cases are widely distributed along Fongafale, one atoll, Amatuku and three outer islands, Nanumaga (9 cases) Nukufetau (14 cases) and Vaitupu (1 case). The outbreak is due to Dengue Virus Type 2 (DENV-2). Currently, 99% of cases have recovered, while 1 remain active. 12 patients (six children and six adults) have been hospitalised since the start of the outbreak, with no current admissions and no deaths reported. Children under 14 years account for 73% of cases ranging in age from 3 months to 80 years. Of the confirmed cases, 149 cases are males and 100 females. The Department of Health continues to conduct case investigations along with physical vector control on Funafuti. The blue alert for DENV-2 remains in effect. – Source: Dengue Fever Outbreak, Situation report #24 (12 December 2025) shared with PPHSN Coordinating Body focal point on 16 December 2025.

Influenza

  • French Polynesia: In French Polynesia, an outbreak of influenza has been declared with 72 influenza A cases confirmed in EpiWeek 49 (1 – 7 December 2025), more than double the number in the previous week. Of these, thirty-one cases required hospitalisation with one case in intensive care. Influenza A(H3N2) is the predominant subtype. Seasonal flu vaccination is available for target groups at all healthcare facilities and selected pharmacies. A red alert for Influenza A remains in effect. – Source: Bulletin de surveillance sanitaire de Polynésie française n°46 - 2025 shared with PPHSN Coordinating Body focal point on 16 December 2025.

  • Federated States of Micronesia: In the Federated States of Micronesia, the Yap Communicable Disease Report for EpiWeek 49 (1 – 7 December 2025) highlights a significant surge in influenza-like-illness (ILI) with 136 cases reported, more than double the previous week, prompting the Yap EpiNet team to declare an influenza outbreak on 8 December 2025. The surge in ILI was detected in the outer islands, namely Woleai Atoll, Lamotrek and Elato. As of 15 December 2025, total of 53 new ILI cases was reported by OPD Main Hopsital bringing the cumulative total since 16 November 2025 to 434 cases. The laboratory confirmed 58 infuenza A cases, including two subtyped as A(H3) and 3 respiratory syncytial viruses (RSV) infections. The most affected age group is 0-4 years with mainland Yap being the most affected area. A red alert for Influenza is added. – Sources: Yap Communicable Disease Report for Week 49 and State Department of Health Services, Situational Report No. 04 (15 December 2025) shared with PPHSN Coordinating Body focal point on 16 December 2025.

Pertussis/Whooping cough

  • New Zealand: As of the week ending on 5 December 2025, weekly pertussis cases in New Zealand remained stable with 49 cases reported as compared to 48 in previous week ending on 28 November, bringing the total reported cases since the beginning of 2025 to 2,497. According to the latest report from the New Zealand Institute for Public Health and Forensic Science (PHF Science), 3,434 confirmed, probable and suspect cases have been notified since the start of the national epidemic on 19 October 2024. Of these, 299 cases (9.3%) have required hospitalisation with one reported death. Out of the 288 cases in infants under 1 year, 146 (52%) have been hospitalised. The blue alert remains in effect. – Sources: Pertussis dashboard and Pertussis Report 18 October–14 November 2025 accessed on 16 December 2025.

Other Information:

Dengue

  • Federated States of Micronesia: As of 9 December 2025, a laboratory confirmed dengue case was reported in Chuuk, Federated States of Micronesia (FSM). The local case had travelled from the Mortlocks (Satowan) one week prior to seeking medical care at the hospital on 14 November 2025. Investigations continue with response plan underway. – Source: Case report shared with PPHSN Coordinating Body focal point on 11 December 2025.

Measles

  • Canada: In Canada, for EpiWeek 49 (30 November – 6 December 2025) there has been 32 new confirmed measles cases bringing the total to 5,329 cases (4,956 confirmed, 373 probable) making it the country with the highest number of reported cases in the Region of the Americas, with persistent transmission in provinces like Alberta, British Columbia and Manitoba. – Source: Government of Canada Measles and rubella weekly monitoring report Epi-week 49: 30 November - 6 December 2025 accessed on 16 December 2025.

  • New Zealand: In New Zealand (NZ), 31 confirmed measles cases have been reported, of which 28 are no longer infectious. The measles locations of interest continue to be updated. Residents are urged to monitor for symptoms and to call their healthcare provider if unwell and check their immunisation status. – Sources: New Zealand Health: Measles outbreak update - Monday 15 December 2025 and Measles locations of interest accessed on 16 December 2025.

  • United States: In the United States, the CDC reported a total of 1,912 measles cases across 43 U.S. jurisdictions as of 9 December 2025, with 87% of these cases linked to forty-seven outbreaks. The majority of cases are among unvaccinated individuals (92%), and 11% of the cases have resulted in hospitalization. There have been three confirmed deaths. The 43 jurisdictions that have reported measles cases are: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Jersey, New Mexico, New York City, New York State, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, Wisconsin, and Wyoming. – Source: CDC Measles Cases and Outbreaks Update as of 16 December 2025, accessed on 16 December 2025.

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